1. Field of the Invention
The present invention relates in general to the field of information handling system power management, and more particularly to a system and method for information handling system power management by variable direct current input.
2. Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
Information handling systems perform a wide variety of functions that consume different amounts of power. For example, simple web browsing or e-mail functions typically consume relatively little power while more computationally intensive functions tend to consume more power, such as running math applications or playing games. Power consumption also increases with the use of peripheral devices, such as playing movies in an optical drive. Generally, information handling systems have power supplies that are capable of providing power to operate components at their highest power consumption levels. Power supplies generally accept power from an external alternating current source, convert the power to a set direct current voltage level and then supply power to components through power rails that carry power direct current voltage adapted to components of the power rail. As an example, an AC-to-DC power adapter converts 120 VAC provided at an outlet to 12 VDC and then a power supply converts the 12 VDC to 5, 3 or 1.5 VDC that are used by components, such as CPUs or chipsets. Desktop information handling systems typically include the AC-to-DC converter in the housing that holds other electronic components while portable information handling systems typically use an external AC-to-DC converter that connects to the housing with a cable that provides a DC Voltage.
Over time, information handling system components have developed improved processing capabilities, however, these greater processing capabilities have often meant increased power consumption. For a number of reasons, increased power consumption has had the greatest impact on portable information handling systems. One reason for this is that portable information handling systems are designed to run on internal batteries so that greater power consumption means reduced battery charge life. Another reason is that portable information handling systems operate on external power with a DC voltage cable coupled to the system housing. In systems that have relatively low power consumption, the external AC-to-DC adapter operates at 12 or 14.5 VDC, however, in systems with greater power consumption, such as power consumption of 90 Watts or greater, the external AC-to-DC adapter typically operates at a higher voltage in order to reduce the current needed for a given power consumption, such as at 19.5 VDC. For example, operating at 19.5 VDC instead of 12 VDC allows current of 4.6 A instead of 7.5 A. The lower current used with higher voltage levels allows for a smaller diameter cable between the AC-to-DC adapter as well as smaller DC connectors and parts with reduced current ratings at the power input loop of the power supply within the information handling system. A disadvantage to the use of a higher DC Voltage input is that DC-to-DC converters of the information handling system tend to operate less efficiently at the higher Voltage levels.